Communication infrastructures suitable for mobile users (in particular though not exclusively, cellular radio infrastructures have now become widely adopted. Whilst the primary driver has been mobile telephony, the desire to implement mobile data-based services over these in infrastructures, has led to the rapid development of data-capable bearer services across such infrastructures. This has opened up the possibility of many Internet-based services being available to mobile users.
By way of example, FIG. 1 shows one form of known communication infrastructure for mobile users providing both telephony and data-bearer services. In this example, a mobile entity 20, provide with a radio subsystem 22 and a phone subsystem 23, communicates with the fixed infrastructure of GSM (Global System for Mobile communications) PLMN (Public Land Mobile Network) 10 to provide basic voice telephony services. In addition, the mobile entity 20 includes a data-handling subsystem 25 interworking, via data interface 24, with the radio subsystem 22 for the transmission and reception of data over a data-capable bearer service provided by the PLMN; the data-capable bearer service enables the mobile entity 20 to communicate with a service system 40 connected to the public Internet 39. The data handling subsystem 25 supports an operating environment 26 in which applications run, the operating environment including an appropriate communications stack.
More particularly, the fixed infrastructure 10 of the GSM PLMN comprises one or more Base Station Subsystems (BSS) 11 and a Network and Switching Subsystem NSS 12. Each BSS 11 comprises a Base Station Controller (BSC) 14 controlling multiple Base Transceiver Stations (BTS) 13 each associated with a respective “cell” of the radio network. When active, the radio subsystem 22 of the mobile entity 20 communicates via a radio link with the BTS 13 of the cell in which the mobile entity is currently located. As regards the NSS 12, this comprises one or more Mobile Switching Centers (MSC) 15 together with other elements such as Visitor Location Registers 32 and Home Location Register 32.
When the mobile entity 20 is used to make a normal telephone call, a traffic circuit for carrying digitised voice is set up through the relevant BSS 11 to the NSS 12 which is then responsible for routing the call to the target phone (whether in the same PLMN or in another network).
With respect to data transmission to/from the mobile entity 20, in the present example three different data-capable bearer services are depicted though other possibilities exist. A first data-capable bearer service is available in the form of a Circuit Switched Data (CSD) service; in this case a full traffic circuit is used for carrying data and the MSC 32 routes the circuit to an InterWorking Function IWF 34 the precise nature of which depends on what is connected to the other side of the IWF. Thus, IWF could be configured to provide direct access to the public Internet 39 (that is, provide functionality similar to an IAP—Internet Access Provider IAP). Alternatively, the IWF could simply be a modem connecting to a PSTN; in this case, Internet access can be achieved by connection across the PSTN to a standard IAP.
A second, low bandwidth, data-capable bearer service is available through use of the Short Message Service that passes data carried in signalling channel slots to an SMS unit which can be arranged to provide connectivity to the public Internet 39.
A third data-capable bearer service is provided in the form of GPRS (General Packet Radio Service which enables IP (or X.25) packet data to be passed from the data handling system of the mobile entity 20, via the data interface 24, radio subsystem 21 and relevant BSS 11, to a GPRS network 17 of the PLMN 10 (and vice versa). The GPRS network 17 includes a SGSN (Serving GPRS Support Node) 18 interfacing BSC 14 with the network 17, and a GGSN (Gateway GPRS Support Node) interfacing the network 17 with an external network (in this example, the public Internet 39). Full details of GPRS can be found in the ETSI (European Telecommunications Standards Institute) GSM 03.60 specification. Using GPRS, the mobile entity 20 can exchange packet data via the BSS 11 and GPRS network 17 with entities connected to the public Internet 39.
The data connection between the PLMN 10 and the Internet 39 will generally be through a firewall 35 with proxy and/or gateway functionality.
Different data-capable bearer services to those described above may be provided, the described services being simply examples of what is possible.
In FIG. 1, a service system 40 is shown connected to the Internet 40, this service system being accessible to the OS/application 26 running in the mobile entity by use of any of the data-capable bearer services described above. The data-capable bearer services could equally provide access to a service system that is with in the domain of the PLMN operator or is connected to another public or private data network.
With regard to the OS/application software 26 running in the data handling subsystem 25 of the mobile entity 20, this could, for example, be a WAP application running on top of a WAP stack where “WAP” is the Wireless Application Protocol standard. Details of WAP can be found, for example, in the book “Official Wireless Application Protocol” Wireless Application Protocol Forum, Ltd published 1999 Wiley Computer Publishing. Where the OS/application software is WAP compliant, the firewall will generally also serve as a WAP proxy and gateway. Of course, OS/application 26 can comprise other functionality (for example, an e-mail client) instead of, or additional to, the WAP functionality.
The mobile entity 20 may take many different forms. For example, it could be two separate units such as a mobile phone (providing elements 22-24) and a mobile PC (data-handling system 25) coupled by an appropriate link (wireline, infrared or even short range radio system such as Bluetooth). Alternatively, mobile entity 20 could be a single unit such as a mobile phone with WAP functionality. Of course, if only data transmission/reception is required (and not voice), the phone functionality 24 can be omitted; an example of this is a PDA with built-in GSM data-capable functionality whilst another example is a digital camera (the data-handling subsystem) also with built-in GSM data-capable functionality enabling the upload of digital images from the camera to a storage server.
Whilst the above description has been given with reference to a PLMN based on GSM technology, it will be appreciated that many other cellular radio technologies exist and can typically provide the same type of functionality as described for the GSM PLAN 10.
Recently, much interest has been shown in “location-aware” services for mobile users, these being services that take account of the current location of the user (or other mobile party). A number of different ways exist for determining the location of a mobile entity and FIG. 1 depicts the case of location determination being done in the network (for example, by making Timing Advance measurements for three BTSs 13 and using these measurements to derive location) with the resultant location data being passed to a location server 37 from where it can be made available to the mobile entity concerned and authorised services. Typically, location determination is only done when a location request is received at the location server, the latter then being responsible for initiating location determination and providing the result to the requesting entity. The location server 37 can be connected as a resource accessible via the GPRS network 17.
It is known to pre-pay for use of PLMN resources (typically voice traffic and SMS services) with the subscriber being centrally credited with an amount corresponding to their prepayment; this initial credit amount is decremented according to the subscriber's use of the PLMN resources until no more credit exists at which time provision of services is suspended. The subscriber can replenish their credit amount by making additional payments generally at any time either before or after the initial credit amount has been used up. The use of network resources is tracked at key points (typically the MSC) which generate billing records for billable events, these records being passed back to the central accounting system where they are matched against the subscriber—if the subscriber is on a pre-payment scheme, the current credit amount is then adjusted according to the billing records. The reduction in credit will depend not only on how long a particular resource (e.g. voice traffic circuit) has been used, but also on factors such as time of day and quality of service.
“WO 00/05871 discloses a prepaid system and method for permitting a prepaid subscriber of a cellular wireless telecommunication system to revise call features during a call to debit the subscribers prepaid account on a real-time basis. The prepaid administrative network, in response to real-time call event messages received from call event generation means, revises an initial charge debiting rate to generate a real-time debiting rate used during the call to reduce the prepaid service credit balance.”
“GB-A-2 332 337 discloses a service centre for a telecommunications system in which a subscribed is allocated particular usage amounts in different usage categories. The usage categories of calls made by the subscriber are then monitored and the calls charged at the rates appropriate for the categories concerned; in addition, the remaining usage amounts available in each category are adjusted accordingly. If a subscriber exceeds the amount of usage available to that subscriber in a particular category, the subscriber is charged at an excess call charge rate.”
Current implementations of pre-payment systems lack flexibility and responsiveness and it is an object of the present invention to provide an improved pre-payment method and system